A process for generating an object comprising a plurality of voxels is described in European patent application EP2672692 and shown in FIG. 2A-2B.
In FIG. 2A and in FIG. 2B the object 26 is printed on a substrate 21 and may have steep edges, sides and/or faces 23 approximately perpendicular to the substrate or a direction of such an edge, side or face has a substantial component in a Z direction.
In FIG. 2A a print head 22 is moving in one direction X over the substrate 21 for ejecting marking material towards the substrate 21 according to trajectories 24 in order to realize a complete layer of voxels extending over the whole upper surface of the object 26 in a mono-directional print mode.
FIG. 2B shows a bi-directional print mode wherein a print head 22 is moving in a first direction X over the substrate 21 for ejecting marking material towards the substrate 21 according to trajectories 24 in order to create a complete layer of voxels extending over the whole upper surface of the object 26 and moving in a second direction X1 over the substrate 21 for ejecting marking material towards the substrate 21 according to trajectories 25 for a next complete layer of voxels extending over the whole upper surface of the object 26.
Experiments have revealed that such steep edges, sides or faces 23 are not always very smoothly printed, and marking material of some of the trajectories 27, 28 may land on a wrong place and cause irregularities 29. The marking material is crumbled from the steep edges, sides or faces 23, also due to an air flow in the X direction or the X1 direction caused by the moving print head 22.
An object of the present invention is to provide a method for printing a plurality of voxels of an object such that the printed object has regular faces, sides, and/or edges.